Worm.VBS.DUNIHI.NBJ

 Analysis by: John Rainier Navato

 ALIASES:

Worm.VBS.Dinihou.e (KASPERSKY)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


This Worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

73,223 bytes

File Type:

VBS

Initial Samples Received Date:

13 Jun 2024

Payload:

Drops files, Modifies system registry, Connects to URLs/IPs

Arrival Details

This Worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Worm drops the following copies of itself into the affected system and executes them:

  • %User Temp%\{Malware File Name}.vbs

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • %System%\wscript.exe //B "%User Temp%\{Malware File Name}.vbs"

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

This Worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Malware File Name} = wscript.exe //B "%User Temp%\{Malware File Name}.vbs"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{Malware File Name} = wscript.exe //B "%User Temp%\{Malware File Name}.vbs"

It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\{Malware File Name}.vbs

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

Other System Modifications

This Worm adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\{Malware File Name}
(Default) = {true or false} - {Date of first execution on the system}

Propagation

This Worm drops the following copy(ies) of itself in all removable drives:

  • {Drive Letter}:\{Malware File Name}.vbs → attributes set to System & Hidden

It creates shortcut files (.LNK) disguised as folders or files located on the affected drives pointing to the malware copy.

Backdoor Routine

This Worm executes the following commands from a remote malicious user:

  • "execute" → Executes arbitrary command from the C&C server
  • "update" → Updates malware code and restart the malware
  • "uninstall" → Uninstalls the malware
  • "send" → Downloads a file from the C&C server, saves it in a specified directory and run it
  • "site-send" → Downloads a file from the C&C server and run it
  • "recv" → Sends a file from a specified URL to the C&C server
  • "enum-driver " → Retrieves list of drives
  • "enum-faf" → Retrieves information about files and folders in a specified directory
  • "enum-process" → Retrieves information about running processes
  • "cmd-shell" → Executes a command using Command Prompt and retrieves its output
  • "delete" → Deletes a file or folder
  • "exit-process" → Forcefully terminates a process and all its children
  • "sleep" → Running script sleeps for a specified amount of time

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}ip.biz:82/

However, as of this writing, the said sites are inaccessible.

Rootkit Capabilities

This Worm does not have rootkit capabilities.

Information Theft

This Worm gathers the following data:

  • Computer name
  • Username
  • OS name
  • Volume serial number
  • Antivirus programs installed in the system

Other Details

This Worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\{Malware File Name}

It does the following:

  • It sets the attributes of non-LNK files and folders in the infected drive to System & Hidden

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.402.05

FIRST VSAPI PATTERN DATE:

13 Jun 2024

VSAPI OPR PATTERN File:

19.403.00

VSAPI OPR PATTERN Date:

14 Jun 2024

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

    • Downloader.VBS.TRX.XXVBS82EFF050

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {Malware File Name} = wscript.exe //B %User Temp%\{Malware FIle Name}.{Malware FIle Extension}
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • {Malware File Name} = wscript.exe //B %User Temp%\{Malware FIle Name}.{Malware FIle Extension}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\{Malware File Name}
    • (Default) = {true or false} - {Date of first execution on the system}

Step 6

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\{Malware File Name}

Step 7

Search and delete these files

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\{Malware FIle Name}.{Malware FIle Extension}
  • %User Startup%\{Malware FIle Name}.{Malware FIle Extension}
  • {Infected Drive}:\{Malware File Name}.vbs
  • {Infected Drive}:\{Created LNK files}

Step 8

  1. Open a command prompt.
    • For Windows 7 users, click Start, enter CMD in the Find input field, and press Enter.
  2. In the CMD console, enter the following:

    ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][filename] [/S [/D] [/L]]

    Where:
    + Activates an attribute
    - Disables an attribute
    R Read-only file attribute
    A Archive file attribute
    S System file attribute
    H Hidden file attribute
    I Indexed file attribute without content
    [drive:][path][filename]
    Specifies one or more files in the current folder and all its subfolders
    /S Processes the corresponding files in the current folder and all its subfolders
    /D Process folders
    /L Act on the attributes of the symbolic link instrad of the target of the symbolic link
    Example:
    To make all files and folders (including subfolders visible in drive D:
    ATTRIB –H D:\* /S /D
  3. Repeat the step above for folders and files from other drives or directories.

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.VBS.DUNIHI.NBJ. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 10

Scan your computer with your Trend Micro product to delete files detected as Worm.VBS.DUNIHI.NBJ. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check the following Trend Micro Support pages for more information:


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